Laptop may have overheated if it completely shut down... Add ons may contain bugs which are messing up gameplay... Seeing as it's not very old I'd check to see if your wifi is compatible or if the graphics setting is slowing you down etc hope this helps xx

you must be careful when modding, sometimes there are conflicts and it will cause a crash. Most times thers a warning about clashing mods, but not always. Id start removing your most recent add-ons until its resolved.